Preheat oven to 325°F (160°C). Butter a 9-inch springform pan. Mix wafer crumbs and 5 tbsp melted butter, press into bottom of pan, and bake for 10 minutes. Set aside to cool.

Lower oven to 300°F (150°C). Beat cream cheese until smooth, add 3/4 cup granulated sugar, then eggs one at a time. Mix in sour cream and 2 tsp vanilla. Fold in melted chocolate.

Whisk egg yolks, brown sugar, evaporated milk, and 4 tbsp butter in a saucepan over medium heat until thickened, 5-7 minutes. Remove from heat, stir in remaining 1/4 cup sugar, 1 tsp vanilla, coconut, and pecans. Cool 10 minutes.

Layer two-thirds of batter into crust, dollop half of swirl, and swirl with a knife. Top with remaining batter and remaining swirl, then lightly swirl again.

Bake until edges are set and center wobbles gently, 60-70 minutes. Turn oven off, crack door, and leave cheesecake inside for 1 hour. Cool completely on counter, then refrigerate uncovered at least 4 hours.

Run a warm spatula around the pan edge, remove ring, and slice with a hot knife. Serve cold.